1. Field of the Invention
The present invention relates to a molding method.
2. Discussion of the Related Art
In the preferred embodiments of the present invention, a molding apparatus is used to hold mold(s) which encapsulate, or mold onto, glass or plastic sheets of the type which are commonly employed as glazing closures in present day vehicles such automobiles and the like. In addition to such glazing sheets being bent to precisely define curvatures dictated by the configuration and size of openings in the vehicle body, in order to meet strict quality standards of manufacturers, it is necessary to mold onto or encapsulate to the sheets of material items such as a gasket around a predetermined portion of the sheet of material. Items such as mounting brackets or studs may also be applied at the location of the gasket or at other positions on the surface of the sheet.
Encapsulating sheets of glass or plastic requires the use of a relatively large mold platen. In order to obtain a large platen, one must purchase a very large, high pressure, molding machine.
U.S. Pat. No. 4,561,625 discloses a mold structure for forming a polymeric gasket around a predetermined portion of a sheet of transparent material such as glass. The mold structure includes two cooperating mold sections for defining a chamber for receiving the transparent sheet. A seal is positioned about the periphery of the chamber and is utilized to resiliently support the sheet within the chamber. Also the seal cooperates with a predetermined portion of the transparent sheet for defining a gasket cavity having a configuration corresponding to the gasket to be formed on the sheet of transparent material.
U.S. Pat. No. 4,762,481 discloses a mold for forming a window assembly which includes a transparent glass sheet and gaskets formed by curing a polymeric gasket material in situ on the glass sheet to encapsulate a marginal peripheral edge portion thereof. A glass sheet to be utilized in a vehicle has a front edge, rear edge, and a lower edge to each of which is adhered such a gasket. In addition, a bracket means for attachment to a scissor linkage for raising and lowering the window can be secured to the lower edge of the window.
U.S. Pat. No. 4,584,155 discloses a method for molding surface structure onto the surface of a glass sheet.
U.S. Pat. No. 5,108,687 discloses a device for at least partially encapsulating a border of a substantially sheet shaped element. The device contains a cavity formed by an elastically deformable member having a profile which extends along an encapsulation border line of the element and which is adapted to be elastically deformed while maintaining a tight contact along the encapsulation border line when pressure is applied thereon in order to follow a irregularities in the element along the border line.
The co-pending application of applicant's assignee, Ser. No. 08/898,207, filed Jul. 22, 1997, and entitled “Molding Method and Apparatus and Parts Produced Thereby”, now U.S. Pat. No. 6,123,535, shows a molding apparatus having a mold base and at least one moveable mold core rotatable into and out of a facing relationship with the mold base. When the moveable mold core is in its closed position, it cooperates with the mold base to define a mold cavity. The mold base may be shaped so as to aid in forming a part, or to hold a sheet of material onto which molding material is to be deposited so as to encapsulate the part on one or more edges or surface regions. Structure may be also encapsulated onto the surface of the material during the molding operation.
The above-mentioned patents show various window assemblies and methods to make the same. The apparatus to make the devices shown often involve large and complicated molding presses. This often times necessitate the devices being made at a separate plant and shipped for installation, for example, to an automobile assembly plant, rather than being manufactured on site, or nearby. Also, such machines are large and costly. Cost amortization requires that multiple molds are changed into, and out of, the machines to manufacture different parts. Due to this, such machines are compromised in size and performance. Thus, those skilled in the art continued to search for a compact molding apparatus which could be moved easily from one place to another, and hold mold(s) in such a way that they are easily and quickly interchangeable.